Summary of Work: The Baltimore Longitudinal Study of Aging (BLSA), the NIA's major research program on human aging, has been conducted at the Gerontology Research Center since 1958. The study represents a consortium of scientists who work to characterize normal and pathological aging. The BLSA consists of a series of longitudinal and cross-sectional studies oriented toward description, identification of mechanism, prediction and intervention in human aging processes. The scientific goals include identifying age differences among individuals and changes in individuals over time; to characterize transitions from normal to pathological aging; to determine the relative contribution of aging, disease processes, cohort effects and secular effects; to expand scientific understanding about predictors and risk factors for specific diseases and for other end points related to successes and failures of adaptation to aging processes; and where possible to explore mechanisms for normal and/or pathological changes. GRC scientists working with BLSA are assigned to 10 sections of 6 laboratories. The Chief, LSS, is the Director, BLSA and LSS staff administer and manage the BLSA operations and the clinical evaluations of the research volunteers. LSS scientists also conduct research with the BLSA. Responsibility for data management of the BLSA was transferred to the Research Resources Branch during the previous fiscal year. The BLSA Executive Committee, an internally compromised committee of GRC scientists and the Director, BLSA, is responsible for oversight of BLSA operations and research. This Committee replaced the dormant BLSA Steering Committee, and is responsible for making major administrative and scientific decisions for the study.